The present invention pertains to an automatic closure for elastically deformable, tube-like or bottle-like containers having a dispensing neck for pasty or liquid media with a dispensing opening, which is arranged in a front wall of a hood cover and can be closed from the inside by a stopper-like closing member movable in the axial direction of the dispensing opening, wherein the hood cover is arranged on a housing that can be attached to the dispensing neck and wherein the closing member is part of an elastic membrane wall of a hood-like hollow body, which consists of an elastic material as a whole and surrounds with an at least approximately cylindrical wall section an inner ring wall of a chamber, which is closed by a bottom, is arranged within a hollow space of the housing through which the medium flows and is connected to the environment by at least one ventilating channel, which is arranged in a radial web and connects the inner ring wall to the housing.
A closure of this type has already been known from WO 99/07614 (PCT/GB 98/02326).
In the case of such closures, the dispensing of the medium is brought about by generating an overpressure inside the container by applying pressure to the side walls of the container, which said overpressure also affects the membrane wall and causes same to remove the closing member from the dispensing opening of the hood cover in order for the medium to be able to be dispensed through this dispensing opening. When the dispensing operation is terminated and the manual pressure on the wall of the housing is no longer present, the wall of the housing shall again return to its original shape due to its elastic restoring forces. However, the volume of the interior space is again increased as a result at the same time, so that outside air must flow into the interior space in order for an equalization of the atmospheric pressure to be able to take place.
Depending on the nature of the medium forming the contents of the container and/or of the plastic restoring forces of the container wall, it may be necessary to additionally ventilate the interior space of the container, which is filled with the medium, or of the closure after a dispensing operation to enable the container or its indented side walls to be able to rapidly return to the original shape.
To take this circumstance into account, an additional one-way valve is provided for ventilating the interior space of the container in a closure similar to the closure of this type, which is described in WO 00/07900 (PCT/GB 99/02522). This one-way valve comprises a separate, axially movable closing member and a passage opening, which is arranged in the bottom of the chamber formed by the inner ring wall. The closing member comprises a ring-shaped closing surface, which lies sealingly on an opposing surface of the passage opening of the bottom when a corresponding pressure is applied to the closing member, which occurs, e.g., during the deformation of the container during a dispensing operation.
This axially movable closing member is guided by finger-like holders and its axial movement is limited. It consists of a dimensionally stable, i.e., non-elastic material and can be moved only as a whole. It is always completely surrounded by the medium to be dispensed. Reliability of the function may be jeopardized at certain viscosities of the medium. When only small amounts of the medium reach the valve seating surface or via this surface the interior space of the chamber at the end or at the beginning of a dispensing operation, this may lead to a loss of the ability of the entire closure to function.
In addition, the closing member of this one-way valve is an additional component, which is to be manufactured separately and must be mounted later and it therefore represents an additional cost factor in the manufacturing costs.
The basic object of the present invention is to provide a closure of the type mentioned in the introduction, in which the suction ventilation of the container, which is necessary at weak restoring forces of the elastic container walls, is achieved by means of a valve arrangement, which is inexpensive in terms of both manufacture and assembly and which also ensures at the same time that the medium in the container or in the housing of the closure can never enter the chamber or a ventilating channel under any circumstances.
This object is accomplished according to the present invention by the inner ring wall being surrounded by a second ring wall, which forms an annular groove with the inner ring wall with the annular groove having at least one axial ventilating opening, which connects the ventilating channel to the hollow space surrounded by the second ring wall. The cylindrical wall section of the hood-like hollow body is provided with an elastic lip, which separates the ventilating opening having the function of a one-way valve from the hollow space.
The present invention creates an automatic closure of this type, which also makes possible the ventilation of the interior space of the container and of the interior space of the closure body, but the one-way valve of which does not require an additional component, on the one hand, and does not cause additional assembly costs, and in which the reliability of function is guaranteed at a substantially greater extent than in the prior-art one-way valve, because the elastic lip is lifted off from its opposing surface only partially and minimally when atmospheric air is indeed flowing through the opening closed by the lip into the interior space.
The lip may be designed as a circular ring lip and may lie sealingly on a bottom surface of the annular groove in both the inoperative state and under overpressure and allows air to flow into the hollow space under vacuum in the hollow space. The lip may also be designed as a ring lip projecting to the outside in a truncated cone-shaped manner and may lie all around sealingly on the second ring wall in both the inoperative state and under overpressure in the hollow space and allows air to flow into the hollow space under vacuum in the hollow space.
The second ring wall may have, axially outside the ring lip, radial perforations, via which the hollow space surrounded by it is in connection with a ring chamber, which surrounds the second ring wall and which is in turn in connection with the interior space of a connection pipe that can be attached to the dispensing neck of the container and, in the mounted state, with the dispensing neck of the container.
A concentric arrangement in relation to the two ring walls, which are concentric to one another, the hood cover is mounted on the housing rotatably around the common axis. The hood cover has a ring-shaped closing wall, which sealingly surrounds the second ring wall and has perforations, which can be brought into an overlapping position with the perforations of the second ring wall by rotating the hood cover in order to connect the ring chamber with the hollow space within the second ring wall or to separate the ring chamber from the hollow space as desired.
The angle of rotation of the hood cover is limited by the correspondingly arranged rotation limiters to a value (xcex2) that is greater than the opening angle (xcex1) of the perforation of the second ring wall, which is the largest perforation in the circumferential direction.
The hood cover is provided with a sealing ring lying sealingly on the inner surface of a cylindrical housing wall of the housing.
The hood cover is fastened to the housing by means of a cylindrical coupling wall or by means of ring sector-like coupling wall elements, which have radially inner locking cams and extend with these under a radially projecting ring collar of the housing.
The present invention will be explained in greater detail below on the basis of the drawings.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention is illustrated.